Assessments of transportation investment from a social efficiency viewpoint are absent from transportation policy analysis and marketing practice. This is mainly due to lack of tools capable to assess the role of transportation infrastructure investment on the provision of activity opportunities to residents of each locality. In this paper, we demonstrate a method that identifies specific locations in an entire state where resource allocation has succeeded in maximizing benefits to the public. In addition, the method based on the Theil inequality index and the Geographic Information System maps derived from this technique show which locations in California fail to be equitable and require their residents to travel excessively to pursue the same amount of activities when compared to other locations around the state where travelling enables better time allocation. Inequality is measured through the prism of accessibility. Accessibility is here considered as the amount of roads and activity opportunities reachable within a given travel time buffer. These activities include retail, education, health, manufacturing, and all other activities. The mapping tool thus developed shows which residents suffer the most from suboptimal time allocation and what type of investment is needed to alleviate this suffering. In addition to the substantive findings about and mapping of the relative investment inequality in California, this paper presents a method to capture the multi-scale structure of inequality in a multi-objective environment.
Abstract